The invention relates to a teat cup in accordance with the preamble of claim 1 and an appropriate liner.
Such a teat cup disclosed, for instance, in CH-PS 628 496 includes a teat cup sleeve in which a liner is accommodated.
In order to achieve a safe opening in the suction cycle, the known liner is clamped in the teat cup sleeve, a liner head being fixed to an upper clamping position of the teat cup sleeve, while the end portion distant from the liner head is fixed to a lower clamping position. This end portion of the liner is connected to a negative pressure source, for instance a vacuum pump, via a milk hose. An exterior space to which negative pressure or atmospheric pressure can be applied via an appropriate connection is formed between the teat cup sleeve and the liner clamped therein. By increasing the pressure in the exterior space vis-à-vis the teat receiving space defined by the liner the circumferential walls of the liner can be brought into contact with the teat section by section during the massage phase.
In the known solution a closing means is provided in the milk hose connected to the liner via which closing means the connection to the negative pressure source can be shut off or throttled. This closing means is realized by a membrane-like configuration of the milk hose wall.
It is a drawback of this known teat cup that in the interior space below the teat there remains a relatively large volume, because the shut-off from the vacuum is only effected in the subsequent milk hose. The relief of the teat from the vacuum is impeded by the relatively large volume.
When using known teat cups having normal-wall liners, it has turned out that due to an infavourable strenuous massage of the teat by the walls of the liner an optimal milking is not ensured especially in the case of sensitive cows of modern breedings.
In order to eliminate this drawback, it is suggested in EP 0 593 563 B1 to design the liner to have a comparatively small wall thickness. Although this thin-wall liner is adapted to prevent the teat from being overstrained even in the case of sensitive cows, however, it is difficult that due to the thin wall an opening of the liner required for the milk withdrawal in the suction phase is not ensured. Moreover neither a desired sequence control of the massage nor an optimum sealing at the teat can be achieved by such thin-walled liners.
In U.S. Pat. No. 3,659,598 a liner having reinforced wall portions and intervening thin-wall portions is disclosed.
Compared to this, the object underlying the invention is to provide a teat cup and an appropriate liner which can also be used with sensitive cows and in which the opening during the suction phase and an optimum sealing and adhesion during the massage is ensured.
This object is achieved, with respect to the teat cup, by the combination of features of claim 1 and, with respect to the liner, by the combination of features of claim 20.
In accordance with the invention, in the hose part of the liner receiving the teat thin-wall portions are formed which permit a punctual or area-restricted massage of the teat or a closing to the negative pressure source.
Due to the support via the thick-wall portions of the liner, the thin-wall portions can be designed such that even with a clamped liner and a pressure compensation in the interior and exterior spaces only a negligible longitudinal tension is applied thereto so that a radial excursion of the membrane-shaped thin-wall portions is supported.
Moreover, the adhesion of the teat cup to the teat can be improved by a suitable positioning of these thin-wall portions so that the liner can be prevented from both slipping off and climbing during milking.
A possibly required axial tension or restoring force in the almost circular cross-section of the liner during the suction phase can be assumed by the thicker wall portions or anchoring, supporting or web members. The thin-wall portion mainly serves for massage or for closing and supporting the teat and is designed so that the thin-wall portion is either extremely extensible at least in one direction between two thicker wall portions, anchoring, supporting or web members or has a greater length than the direct distance between the anchoring, supporting or web members.
The drawbacks regarding adhesion and massage existing with conventional teat cups are largely eliminated by the use of thin-wall portions designed according to the invention in a teat cup, a good adhesion of the teat cup to the teat not causing any constriction is achieved and at the same time it is possible to improve the course of massage physiologically by stopping the massage upon the beginning of the suction cycle first at the teat base and then at the tip of the teat.
The use of thin-wall portions according to the invention for massaging the teat also permits to utilize the quick reaction of such thin-wall portions to differences in pressure and thus provides the opportunity to carry out an intensive stimulation at high pulse frequences. Such a stimulation of vibration is especially effective, because it can be effected while simultaneously closing the vacuum from the teat receiving space. This is in contrast to the conventional method in which the teat is stimulated under vacuum.
Such thin-wall portions in the liner receiving area can fulfill various tasks depending on the constructional arrangement, they can have an annular shape and can be dented in the longitudinal section or undulated and/or can have different wall thicknesses with respect to each other. The teat receiving area is considered to be that part of the liner which is suited for receiving the teat in terms of diameter. This area may have a greater axial length than the teat, however.
In order to improve the adhesion, a thin-wall portion is used, e.g. above the clamping of a teat cup sleeve below the liner head or directly below an inserting ring, wherein atmosphere is applied to the outside of the thin-wall portion or the latter is adjacent to a closed exterior space by the volume of which the extension of the thin-wall portion can be influenced (FIGS. 4, 6, 7). The exterior space adjacent to the outside of the thin-wall portion may be an annular space or a chamber. A common exterior space may be assigned to plural thin-wall portions.
If the head is supported close to the thin-wall portion, the head remains more movably (FIG. 4). It is also possible to apply a control pressure to this exterior space by means of a connecting line so that a difference in pressure from the teat receiving space (interior space) is brought about. So, e.g. in the event of a drop of vacuum in the interior space or an undesired change of position of the teat cup, an excessive pressure can be controlled to be introduced so that an immediate contact of the thin-wall portion with the teat is obtained.
If this chamber is connected to the pulsation of a pulsator, such a thin-wall portion can be used to improve the adhesion, massage or stimulation, because especially at the beginning of the massage cycle it brings about an earlier contact with the teat by applying a differential pressure from the teat receiving space to the outside without causing a constriction of the teat at the base. Axially seen, there can also be effected a time sequence of the contact with the teat and the massage of the teat by the liner, resp., by the fact that, e.g., seen from the teat base downwards the successive hose portion of the liner restricting the teat receiving space has a appropriately thicker wall or changes to a smaller diameter. If necessary, in the hose portion the folding direction with respect to the cross-section can be defined by ribs or different wall thicknesses or an oval shape.
Furthermore, plural ones of the thin-wall portions according to the invention can be arranged axially one beneath the other so that they become effective over the entire teat area. Exterior spaces can be assigned to the thin-wall portion so that a sequence control can be executed in that the latter interconnects exterior spaces assigned to one or more thin-wall portions through conduits or bores, advantageously provided with possibly different throttle elements. Likewise the individual exterior spaces of the thin-wall portions can be separately controlled.
According to another embodiment of the invention a plurality of small-area thin-wall portions is radially and axially spread over the teat receiving area in the hose part of a liner, wherein these thin-wall portions can be predetermined as to their shape and are preferably designed to be circular or oval. It can moreover be advantageous to arrange these thin-wall portions spread like a net over the entire teat receiving area of the hose part (FIG. 4).
It is another embodiment of the invention to design these thin-wall portions as longitudinal paths between thicker-wall webs preferably in the teat receiving area of the hose part, wherein in this case the thin-wall portion can also be axially tensioned, if the same is radially movable or dented between the longitudinal webs, wherein, seen in cross-section, one or more of such thin-wall portions can be distributed to be juxtaposed at the periphery.
The thin-wall portions according to the invention permit the design of a teat cup without the previously usual exterior space between the circumferential wall of the liner and the inner circumferential wall of the teat cup sleeve. In this embodiment the massage is exerted solely through the thin-wall portions to which alternately a vacuum or atmosphere and/or pressurized air is applied through a duct by means of a pulsator control. The other teat reception can be surrounded without clearance by a sleeve of a rigid or flexible material which is closely adjacent to the teat cup sleeve or can be designed to have an inherent stability due to an appropriate dimensioning of the wall. A teat cup designed in this way has the additional advantage of an easier handling by the considerably smaller diameter (FIGS. 6-11).
It is especially advantageous if the liner according to the invention is provided with a closing by which the connection to the negative pressure source can be throttled or shut off. According to the invention, this throttling or shut-off of the connection is effected via one of the thin-wall portions of the liner formed in the teat receiving area.
Although it is known per se already from the prior art according to CH-PS 628 496 mentioned in the beginning to provide a closing between the negative pressure source and the liner, however this closing is formed in the milk hose which is formed, depending on the embodiment, following the liner or else in the area between the negative pressure source and a claw. By the solution according to the invention to integrate this closing into the teat receiving area, the volume in the interior space below the teat to the closing element can be considerably reduced to shut off the vacuum. Moreover, in the solution according to the invention the thin-wall portion may assume a double function which, on the one hand, consists in shutting off the closing and, on the other hand, in the massage of the teat.
The closing is formed at a distance below the teat in the interior of the liner.
A preferred embodiment illustrates a closing having an at least substantially annular and dimensionally stable sealing or support face which is located obliquely with respect to the longitudinal axis of the liner and a closing wall opposed to this face and getting in contact with the same in the relieving cycle, the closing wall being formed by a thin-wall portion of the liner or by a planar closing element which is supported by the thin-wall portion of the liner or is integrated in the same.
Milking methods which relieve or at least strongly reduce the vacuum at the teat during the massage cycle have great advantages, as is known, regarding the health of the udder and the milk yield. The design according to the invention of a closing located directly below the teat receiving area excels by a particular simplicity and functional safety and ensures a free flow during the milk discharge and during cleaning. Accessory parts which are disturbing in practice and possibly have to be cleaned separately are avoided. It is further especially advantageous that, on the one hand, during the massage cycle a relief of the teat is achieved by an at least extensive closing from the vacuum and, on the other hand, a troublefree milk flow is ensured in the relieving phase of the teat from the vacuum. This is a consequence of the fact that when no milk is flowing a total closing is possible, however, in the case of milk flow, the closing member initially closes only the liquid-free cross-section of the passage and thus the milk can flown off even when the teat is relieved from the vacuum.
This closing may be designed so that the thin-wall portion that effects the closing is simultaneously used for massaging the teat, wherein in this case this thin-wall portion may have an increasing or decreasing wall thickness toward the teat.
It is further possible to ventilate the teat receiving space with atmosphere by means of a duct passed by the closing.
It is a particularly advantageous possibility of the closing according to the invention to obtain a periodical ventilation, which communicates the space below the teat with atmosphere in the suction cycle and thus causes a smooth discharge of the milk collected below the teat, by means of a communicating duct to the atmosphere ending in the wall of the closing face preferably with a nozzle. By this type of ventilation a clearing of the interior space below the teat in the direction of the milk flow is obtained, before the closing is shut in the subsequent massage cycle. When closing the teat receiving space from the vacuum, at the same time the communicating duct can be closed by the thin-wall portion and/or by the closing member, wherein the opening of the communicating duct may be surrounded by an annular ring.
It is also possible to use a flexible elastic nozzle projecting toward the thin-wall portion so that there is also the possibility of a mechanical cleaning by contacting the flexible nozzle through the thin-wall portion or the closing member. This embodiment is particularly advantageous if the closing according to the invention is manufactured as a component of an extruded part.
As an alternative, a cleaning pin adapted to be introduced into the nozzle bore from outside and being movably guided in the teat cup may be assigned to the nozzle.
Depending on the arrangement of the opening of the communication to the atmosphere into the oval annular face of the closing, a change concerning the time of opening or closing of the communicating duct and thus also a change of the admitted air quantity (A/min) is obtained. Concerning the milk quality, large air quantities are not desired, as they entail the formation of free fatty acids. Due to the periodical intake of air directly below the teat it is possible to manage with relatively small air quantities.
This type of ventilation in the suction cycle has further advantages, because the ventilation is effected directly below the teat and thus even in the case of high milk flow there occurs no hydraulic effect which requires large cross-sections of the discharging milk conduit in the previous teat cups and makes such a milker very bulky.
With this type of periodical ventilation in the suction cycle only normal cross-sections, as shown in FIG. 4, of the milk conduit leading away from the teat cup which correspond to the milk flow are required so that a milker of this type is particularly easy to handle.
By arranging a valve in the communicating passage to the atmosphere a periodical ventilation is possible also in the massage cycle.
In all liners having one or more thin-wall portions a defined folding during massage is advantageous. This can be achieved by the relation of the wall thicknesses to each other or by an oval shape of the cross-section, or else by an appropriate contact with the inside of the teat cup sleeve. It can be necessary in this context to provide a twisting protection between the teat cup sleeve and the liner by meshing projections and recesses.
In order to obtain a further increase in stimulation the surface of the inside of such a teat cup including thin-wall portions can obtain, e.g., a rough surface structure which stimulates the teat wall similarly to the surface of a calf""s tongue.
Further developments of the invention are the subject matter of the further subclaims.